The present invention generally relates to a screw assembly for positioning a carriage along a carriage guide. More specifically, the present invention relates to a screw assembly apparatus and a method of using the same that allow movement of a carriage along a carriage guide while protecting the interior of the carriage guide from debris.
It is, of course, generally known to employ a screw assembly to drive or to transfer a carriage along a length of the screw assembly. Further, known screw assemblies provide a sealing apparatus to protect the inside components of the screw assembly from debris and other contamination. Such debris may wear internal components of the screw assembly causing failure or malfunction of the screw assembly during operation.
Further, known screw assemblies may have the sealing apparatus disposed along the length of the carriage guide to prevent contamination of the inside components of the screw assembly. For example, a known sealing apparatus includes two pieces of overlapping rubber flaps disposed along the length of the screw assembly. The rubber flaps open and close around the carriage as the carriage moves longitudinally along the screw assembly. However, known sealing apparatuses may add to the cost and complexity of the screw assembly. Further, known sealing apparatuses may wear from frequent use and may ultimately, require replacement, causing additional operation costs.
Further, screw assemblies are known which use intermediate supports to prevent a screw within the screw assembly from bowing or otherwise losing its shape at high speeds. This is generally referred to as xe2x80x9cwhipping.xe2x80x9d More specifically, whipping may occur when the screw reaches certain critical speeds causing the length of the screw to bow and otherwise lose its shape thereby interfering with the carriage as the carriage attempts to move along the length of the screw. Further, whipping of the screw may cause damage to the screw assembly if the screw hits parts of the screw assembly as it is whipping. Intermediate supports that are used to prevent whipping may fix the screw in place; however, the known intermediate supports also add to the cost and complexity of the machine.
A need, therefore, exists for an improved screw assembly apparatus and a method of using the same that overcome the problems associated with currently known screw assembly apparatuses and methods.
The present invention provides a screw assembly apparatus and a method of using the same. More specifically, the present invention provides a screw assembly apparatus and a method of using the same that allows a carriage to move along a length of a screw and protects the internal parts of the screw assembly apparatus.
To this end, in an embodiment of the present invention, a screw assembly apparatus is provided. The apparatus has a screw having a length. A carriage guide is provided having an opening and further having a length wherein the carriage guide has an interior space inside the carriage guide wherein the screw is disposed within the interior space. A nut assembly has a bore-hole therethrough wherein the screw is disposed through the bore-hole and further wherein the nut assembly is contained within the interior space of the carriage guide. A carriage extends through the opening and attached to the nut assembly.
In an embodiment, the nut assembly engages the screw and moves along the length of the screw via a rotation of the screw.
In an embodiment, a rotator is associated with the screw assembly for rotating the screw.
In an embodiment, a rail is disposed along the length of the carriage guide within the interior of the carriage guide. A slot is provided in the nut assembly wherein the rail within the interior of the carriage guide fits within the slot in the nut assembly.
In an embodiment, the opening runs the length of the carriage guide.
In an embodiment, means is provided for limiting the movement of the carriage associated with the screw assembly.
In an embodiment, a dog is attached to the carriage extending from the carriage.
In an embodiment, the carriage guide has a bottom side wherein the opening is positioned on the bottom side of the carriage guide.
In an embodiment, a pad extends from the nut assembly engaging the nut assembly to the carriage guide.
In an embodiment, a spring engages the pad wherein the spring provides tension to the pad and further wherein the pad positions the nut assembly within the carriage guide.
In an embodiment, end caps are attached to the ends of the screw providing free rotation of the screw.
In an embodiment, the opening is disposed at a corner of the carriage guide.
In another embodiment of the present invention, a method for positioning a carriage is provided. The method comprises the steps of: providing a screw having threads and a length; engaging a nut assembly to the threads of the screw; providing a carriage guide having an opening and further having a length wherein the carriage guide has an interior space running the length of the carriage guide wherein the screw is disposed within the interior space wherein the carriage guide surrounds the nut assembly; disposing the screw through the nut assembly wherein the nut assembly is contained within the interior space of the carriage guide; and extending a carriage through the opening of the carriage guide wherein the carriage is attached to the nut assembly and further wherein the nut assembly moves along the screw assembly via a rotation of the screw.
In an embodiment, the opening runs the length of the carriage guide.
In an embodiment, a rotator is provided attached to the screw that rotates the screw.
In an embodiment, a limiter is attached to the carriage guide and limits the position of the carriage via the limiter.
In an embodiment, a pad extends from the nut assembly and positions the nut assembly within the carriage guide with a pad.
In an embodiment, the pad is tensioned with a spring, and the pad is forced against the carriage guide via the spring.
In an embodiment, a slot is provided in the nut assembly. A tab is provided on the carriage guide, and the tab is positioned on the carriage guide inside the slot in the nut assembly.
In an embodiment, a dog is attached to the carriage. A pallet having a slot is provided to engage the dog with the slot in the pallet. The pallet is moved by rotating the screw.
It is, therefore, an advantage of the present invention to provide a screw assembly apparatus and a method of using the same that allow a carriage to move longitudinally along a carriage guide.
A further advantage of the present invention is to provide a screw assembly apparatus and a method of using the same that prevent contamination of the inside of the carriage guide.
Yet another advantage of the present invention is to provide a screw assembly apparatus and a method of using the same that reduce the assembly cost of the screw assembly.
And another advantage of the present invention is to provide a screw assembly apparatus and a method of using the same that reduce the maintenance cost of the screw assembly by protecting internal components of the screw assembly from debris or other contamination.
A further advantage of the present invention is to provide a screw assembly apparatus and a method of using the same that provide intermediate support to the screw without the addition of supports to the screw assembly.
A still further advantage of the present invention is to provide a screw assembly apparatus and a method of using the same that allow a carriage to extend from an interior of a carriage guide through an opening on the bottom side of the carriage guide.
Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings.